1. Field of the Invention
The present invention relates to a mechanical speed regulator for an injection pump which has centrifugal weights on its drive shaft. The centrifugal weights shift a regulator or control pin axially against the force of a supplementary feed spring, whereby in operation there is one end of a beam of balance arranged to swing freely and to engage the control pin furthermore in balance or equilibrium with a regulator spring.
With mechanical speed regulators it is desirable that the control spring exerts its force with the least possible friction upon the control pin, since otherwise the control or regulation accuracy suffers. For constructive reasons, as well as because of the proportionality range adjustment and the automatic procedure or steering of the quantity, it is, however, not possible to permit the control spring to engage directly against the pin. Consequently, intermediate members are necesssary, which once again effect friction and damping of the spring force therewith.
2. Description of the Prior Art
As to the arrangement of a speed regulator, reference can be made to U.S. Pat. No. 4,132,206-Straubel et al, issued Jan. 2, 1979 for a schematic representation that shows the elements of a speed regulator or speed control including a portion of a housing and there can be generally stated that the speed regulator or control is connected with a block injection pump. The Straubel et al Patent 4,132,206 described accurately how the speed regulator functions and what a starting supplementary quantity or feed actually is, namely, that the associated fuel injection pump delivers a starting fuel rate exceeding the full-load fuel rate, with excess being maintained while starting the engine up to a predetermined point. An average man skilled in the art who is active in such a field of endeavor must understand in principle how such devices are constructed. However, instead of referring to "starting supplementary feed", then there can be attributed the meaning thereto--extra quantity of fuel needed for starting--. With the Straubel et al patent, the transfer of the forces from the control spring onto the control rod occurs by way of a complicated mechanism with several bearing locations and guide means which all are frictionally loaded or burdened. Consequently, no transfer of the position of the control spring onto the control rod can occur free of losses. Such a system operates with large losses and this means that a small or nominal change of speed of the internal combustion engine is not at all noticed by such a control system and correspondingly also is not balanced or equalized. Disadvantageous with the arrangement of U.S. Pat. No. 4,132,206-Straubel for a mechanical speed regulator is that the forces of the regulator springs must be transferred to the regulator pin by a complicated and friction-loaded or burdened kinematic arrangement. Additionally, the beam of balance is linked simultaneously in the middle region thereof and is adjusted by a very complicated embodiment of adjustment device whereby the beam of balance is loaded in such a manner that in the point of adjustment and in both linkage points positively an increased friction must arise. Such a system operates with great losses. This means that a slight change of the speed of the internal combustion engine is not at all noted or detected by such a control or regulating system and consequently, also cannot be equalized thereby.
The remaining prior art shows no separate speed control or regulator but rather distributor injection pumps with integrated speed regulator or control means. Because of the manner of construction of the distributor pumps there exists no control rod in the conventional sense but rather either the pump drive shaft is shifted so that the pump stroke is changed or valves are actuated which change the invention quantity flowing into the cylinder. For this reason such speed regulator or control means are not comparable with those of the present invention. Accordingly, the Leblanc U.S. Pat. No. 3,871,794 dated Mar. 18, 1975 shows a distributor injection pump with a very complicated arrangement including bearing means and pump elements driven by way of the drive shaft having a frictional force exerted upon the shaft so that the axial shifting thereof certainly is not possible in a fine or sensitive manner nor being possible in small steps.
Approximately the same relationships are shown by the Roosa U.S. Pat. No. 3,219,020 dated Nov. 23, 1965 which fails to recognize that it is not sufficient only to journal the lever having a low friction but rather that it is necessary to arrange all elements, to have low friction so that a transfer of a centrifugal force movement is permitted onto the control elements changing the injection quantity with a low friction. Also, with the Roosa patent there is disadvantageous that a valve is arranged in a bore without other auxiliary means and a rotation of the valve consequently is frictionally burdened or loaded.
The Italian Pat. No. 572,006 of Jan. 18, 1958 likewise shows in a manner similar to both foregoing patents only a distributor injection pump involving all steps or procedures which are frictionally burdened or loaded and that require a relatively high cost or application of force. This however is not compatible with a fine or sensitive adjustment as can be created with the features of the present invention. Attention is directed thereto that the three last mentioned disclosures do not show any speed regulator or control as described by the present invention.